You should not doubt that the intellect, when it begins to be strongly energized by the divine light, becomes so completely translucent that it sees its own light vividly. This takes place when the power of the soul gains control over the passions. But when St. Paul says that "Satan himself is transformed into an angel of light" (2 Cor. 11:14), he definitely teaches us that everything which appears to the intellect, whether as light or as fire, if it has a shape, is the product of the evil artifice of the enemy. So we should not embark on the ascetic life in the hope of seeing visions clothed with form or shape; for if we do, Satan will find it easy to lead our soul astray. Our one purpose must be to reach the point when we perceive the love of God fully and consciously in our heart …

(Diadochos of Photiki)